Method of applying bottle caps



Oct. 12, 1948. E. M. BRIGHT 2,451,273

METHOD OF APPLYING BOTTLECAPS Filed Jan. 8, 1943 2 Sheets-Sheet l GD :11.15; {ria-:Ah- G) ATTOENEYD,

Oct. 12, 1948. E. M. BRIGHT METHOD OF APPLYING BOTTLE CAPS 2 Sheets-Sheet 2 Filed Jan. 8, 1943 Patented Oct. 12, 1948 METHD F APPLYING BOTTLE CAPS Elvin M. Bright, Whitefish Bay, Wis., assignor to Bright Laboratories, Inc., Whitefish Bay, Wis., a corporation of Wisconsin Application January 8, 1943, Serial No. 471,782

2 Claims.

This invention relates to improvements in a method for thermoplastically capping bottles.

It is an important object of the invention to provide a method and means of capping a bottle which, to a large extent, will make use of standard existing bottle capping equipment and will provide a cap which will not interfere with the handling, processing, merchandising, and use of the bottle and its contents in accordance with conventional procedure.

From the standpoint of the process involved, a very important objective is to soften a thickened margin of the bottle cap blank without softening the remainder thereof, and to mold such thickened margin around the cap-receiving bead of the bottle and immediately to harden it thereon. In this connection I propose to utilize infra-red rays or other radiant heat for softening the flange of the bottle cap blank while shielding and thermally insulating the top of the blank from such rays. Infra-red rays are preferred because of the ease with which they may be directed and controlled.

Other objects and advantages are employed in the construction of parts, the combination of parts, the appropriate method steps, and the mode of operation, as will become more apparent from the following disclosure of the invention.

In the drawings;

Fig. 1 is a view largely in side elevation but partially in section showing bottle capping equipment embodying the invention.

Fig. 2 is a view on an enlarged scale showing in side elevation a portion of the feedway through which the bottle cap blanks pass from the hopper to the capper, a portion of the side thereof being broken away to expose the underlying structure.

Fig. 3 is a detail view taken in section on the line 3-3 of Fig. 2.

Fig. 4 is an enlarged fragmentary detail view in axial section through a capping head embodying my invention, showing it in its preliminary relation to the mouth of the bottle to be capped.

Fig. 5 is a view similar to Fig. 4 showing a subsequent relative position of the parts, the bottle having lifted the cap blank from its seat and the die being preliminarily engaged therewith.

Fig. 6 is a View similar to Fig. 4 and Fig. 5, showing the completion of the cap molding operation.

Fig. 7 is a detail view taken in section on line l-l of Fig. 5.

Fig. 8 is a fragmentary detail view taken in section on line 8 8 of Fig. 6.

Fig. 9 is a bottom plan view of the capping die assembly with a portion broken away to expose one of the movable die members.

Fig. 10 is a view partially in side elevation and partially in section illustrating a bottle cap blank made in accordance with this invention.

Fig. 11 is a view partially in side elevation and partially in section showing a bottle cap molded from the blank of Fig. 10 onto the mouth of a bottle.

Fig. l2 is a view in perspective showing the molded cap in place. i

Like parts are identified by the same reference characters throughout the several views.

The bottle cap blank shown in Fig. 10 is made by molding from thermoplastic material which may have a, .softening point in the vicinity of 300 degrees F. This blank l5 has a disk portion i6 provided with a peripheral flange at Il in which the inner face may be approximately cylindrical. The outer side of the ange is preferably shouldered to provide a material increase in thickness at its marginal portion I8, said marginal portion preferably terminating in a flat or substantially fiat face at 20.

The thermoplastic material of which the blank l5 is made, is more fully described in my companion application entitled Plastic, Serial No. 500,455, filed August 28, 1942, now abandoned.

For the purposes of the present application its characteristics are more important than its particular composition. I have found it expedient to obtain the relatively high softening point aforesaid by using a combination of substances which includes two types of asphalt, each of which has undergone partial polymerization before molding. Polymerization may be continued after the molding operation, if this is found desirable,

so as to increase the melting or softening temperature of the material.

The thickening of the peripheral ange in the marginal portion I8 provides the excess of material which is desirable to have for the molding of the cap about the capping bead 2|` with which the bottle 22 is provided. In addition, the flat face at 2Q has substantial area to receive the infra-red radiation from the heating lamps used to soften the blank as a preliminary to the molding operation. At the same time the shoulder provided by the thickening of the marginal portion I8 of the blank shades those portions of the ange H which are contiguous to the disk portion I6 of the blank so as to protect these portions from the infra-red rays. It is important to the success of the capping operation that neither the disk Hi nor the contiguous portions of flange Il should be softened during the operation in which the thickened marginal portions I8 of the blank are prepared for molding.

After the blanks have been molded of suitable material to the form shown in Fig. 10, gaskets 23 of cork, cardboard, composition, or any other material are inserted into the cavity of the blanks i5 so as to cover Vthe exposed inner portions thereof. The gaskets provide a suitable seal against `the mouth of the bottle 22. For the purposes of the present invention the gasket 23 is important not only in sealing the bottle butwin providing thermal insulation which prevents the infra-red radiation or other heat rays frornreaching the disk portion I5 of the cap'or blank.

Cap blanks provided with gasket disks 23 are introduced from time to time into the hopper 24 of the turret type capper shown in Fig. 1, this device being of conventional construction with the exception of the modifications required to adapt itfor the practice of the present invention. v Only the parts so modified are shown in detail. Special capping vheads generally designated by reference character 25 in Fig. 1 carry molding dies instead of the crimping dies commonly used where bottles are to be capped with metal crowns. A special feedway or chute 26 preferably guides the blanks to the heads 25. This feedway differs from the conventional feedway only in the optional respect vof providing for` more vcomplete exposure of the 1j faces of the blanks l5 to receive the infra-red radiation from the source 21. t l

I have found it satisfactory to use lamp type sources'of infra-red radiation and I direct the rays emanating from such source by means of thereectors 28 or lenses 25er both. `The guideway or chute has some means for retaining the cap blanks I5 whichuadmits the radiation from lights A2i`| to the faces 2li-at the thickened margins It!V of the blanks l5. As shown in 2, the recause itji's readily controlled, and secondly, be-v cauee it is clean, and third, and most important, because it penetrates the plastic material of the cap-to a considerable depth in a very short space of time. -I have found three such lamps adequate to raisethe thickened marginal portions I8 of the blanks to molding temperature `at the normal at which the blanks pass ,down the guide chute 25 during normal operation of a capper of the general character illustrated. The blanks 'tend to rotate as they movedown the chute 25, thereby assuring uniform distrbution V,of heat throughout their thickened marginal portions.

t Asis convention in suchmachines, an air jet impulse is supplied intermittently through the Aair `hose 33 in synchronism with the operation of the capper to deliver successive blanks periodically into the capping mechanisms as these rotate in their` turret intorregistry withchute 25. The

rotating means and the means fo'r causing t 4 a temporary supporting member 35 through which there is an opening at 36 to receive the mouth and adjacent capping bead 2| of a bottle 22. the opening 36 is a flange 3'! adapted to receive the cap blank l5 delivered thereto from the chute 26 by means of a guide slot 38. Immediately above the position of the cap blank l5ion the shoulder 3l is a capping die assembly.

A plunger 40 is mounted in a sleeve at M recessed to provide a space for compression spring 42 which acts on the head portion 43 of the plunger to normally maintain it'in the relative positio'nof the parts shown in Fig. 4. The plunger 'head V43 has a number of radial holes in which the molding ldies are individually reciprocable in a generally radial direction. The outer ends of dies 45 are beveled for engagement with the cam surface 45 formed in the inner face of the sleeve 25 adjacent its lower end. At itsinner end each of Vthedie plungers d5 hasfbeveledcam'surfaces @Tand 48 converging toward a central transversely extending apex at` V139i, the contours, of which are lcomplementary `to the contours of the bottle neck portion 5l) immediately beneath its cappingbead M.V Y m U t To maintainthe several vdie plungers 4 5 in their 'predetermined `positions Y in I the bores in which capping mechanism 25, thelbott'le capping bead 2i at the mouth of the'bottie 'picks up tire` cap blank |15, thereby moving the 4rblank from the position in whichyit is shown in Fig. lY to the rela- V tive position in which it appears iii-Fig'. 5. The

at disk portion I6 of the blank vis, now positively engagedrby plunger 45 and its internal gasket is positively compressed against the mouth of .the

bottle. Eurthler relative 4movement between the plungerd and the bottle is iinps'sible. ,Y

v The continued movement f sleeve `4 respecting the bottle will causeltthe cam surface I45 'ofsleev'e 15| to force all of the molding die plungers 55 'radiallyinwardly. The softened marginal portions I8` of the Ybottle: cap trani;V is are molded abont the bottle bead 2 l but those portions f the'cap blank flange il which are immediately"cntiguous to its topor vdisk portion- I6, not having beensoftened sufciently to be p1asticwill retain their rigidity, as'will the disk-portion- !Eof thevcap. I t y The bottle will preferably comei to the capper directly from the `bottling machine or the carbonator, and in order to retain the carbonation of its contentsy (assuming these toconstitute a. carbonated beverageythe bottle and itsfcontents `will both be chilled to almost 32 degrees F. soonas thermally softened plastic flange portions of the cap blank are` pressed against the cold glass of the bottle they will solidify.. VThis Vv'setting of the thermoplastic-on the neck f the bottle occurs so speedily that almost no retention of the mold'ing capper is required to effect a perfectcapping operation' l The resulting cap,.formed vbythemoldingoperation as above described, is shown in Figs. M11 and *12.y Its* lower margin originallyv tlfliclfenedv` and outwardly shouldered, as indicated at iwin Fig;w 10, hasnow been bodily offset inwardly at |88 in each of the areas in which it has beenengaged-by one 0f the radially mereblefQ-mss .OlieSk-4 Between the areas the exces'smaterial provides ribs at About 55 which span the concave surfaces at |80 and are of the greatest importance in rigidifying the cap and rendering permanent its grip upon the capping bead 2| of the bottle.

The inner contour of the prefabricated capping blank is preferably so formed that the gasket member 23 is clamped and pressed against the lip of the opening of the bottle from a point designated by the reference character 60 to a point G2. Furtheremore, the cap IB is so formed that the margin of the blank 23 from 60 to 52 is compressed and terminates in a feather edge portion 64. Originally, the gasket .member was provided with a straight side wall. However, due to the shape of the cap blank, the outer margin of the gasket member has been pinched or squeezed to a feathery edge. That is important, in order to properly seal the bottles.

The beveled surfaces 4l above the molding projections 49 on the several dies 45 force the dies backwardly as soon as the release of capping pressure on the sleeve 4I permits the reaction of spring 42 to urge plunger 4D and plunger head 43 downwardly within the sleeve 4 l. In other words, the forming dies 45 are cam actuated in both directions of inward and outward radial movement, their outward movement being induced by engagement of the dies with the formed and hardened cap.

One of the advantages of the particular composition used in the molding of the cap blank lies in the fact that it is readily frangible. Another advantage of the particular form into which the cap is molded on the bottle lies in the fact that it will respond to a conventional bottle cap remover, The conventional remover is readily engageable with the cap and when engaged therewith, instead of bending the side walls of the cap outwardly as occurs in the removal of a metal crown, the present cap can be removed only by breaking its side walls. These tend to break upon lines which are vertical from the lower margin upwardly toward the disk IB.

While the method will be apparent to those skilled in the art from the foregoing description, it may be helpful to summarize aspects of the method as follows.

Fundamentally, my method involves the sealing of a bottle by molding a thermoplastic body about the bottle mouth and about a gasket which is held to the bottle mouth by the thermoplastic when it sets.

In the preferred practice of the invention the thermoplastic material is prefabricated as a cap blank and such blank is selectively softened at the margins of its depending flange, leaving the top of the blank unsoftened and therefore adapted to transmit the sealing pressure to the gasket as the softened flange margins are molded to the bottle. The softened margins Will ordinarily be molded about the capping bead with which bottles are conventionally provided. The molding and sealing pressure will normally be retained until the thermoplastic material has set. To reduce the setting time the bottle will preferably be cool at the time of molding. With a thermoplastic having a softening temperature as high as that which is preferably used in connection with this invention, it is only necessary that the bottle be at or near atmospheric temperatures. Preferably, however, it will be artificially chilled below 40 degrees F. At this temperature the thermoplastic will set almost instantly upon being molded to the bottle.

In order that the thermoplastic material may be 6 molded it is delivered hot to the molding die. The heat may be the heat of original fabrication but, as herein explained, I prefer to reheat at least the flange portions of the cap blank as a special step of this process. I preferably employ radiant heat and particularly infra-red radiation for this purpose because of the ease with which I am able to control such heat. Although the infra-red radiation penetrates deeply into the flange, the period of exposure is sufllciently short and the top of the blank sufficiently protected so that the blank top retains its rigidity and is not appreciably softened.

In the course of a molding operation I preferably limit the molding pressure to predetermined sectors of the flange which are concavely molded into general conformity with the bottle, leaving intervening reinforcing ribs.

Although the preferred modifications of the capping device method and article have been desscribed, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and dened in the appended claims.

I claim:

1. The method of sealing a bottle having a bead adjacent its mouth with a cap blank having a disk and an annular flange providing a cavity at one side of said disk, said cap blank being prefabricated from thermoplastic molding material, said method including the steps of inserting a sealing gasket within the' cap blank so as to cover the exposed inner surface of the disk, exposing the margin of the flange of said blank to radiant heat directed toward said margin While protecting the top of said blank from heat by the sealing gasket of thermally insulating material positioned in the cavity of the blank, continuing the application of radiant heat to the blank flange until the marginal portions of such flange are softened, the top of the blank remaining unsoftened, applying the blank to the mouth of the bottle to be sealed, pressing the top portion of the blank toward the bottle mouth sufficiently to compress the gasket to seal the bottle mouth, and molding about the bead of the bottle the softened marginal portions of the blank while maintaining the sealing pressure on the gasket.

2. The method of sealing a bottle having a. bead adjacent its mouth with a cap blank having a disk and an annular flange providing a cavity at one side of said disk, said cap blank being prefabricated from thermoplastic molding material, said method including the steps of inserting a sealing gasket within the cap blank so as to cover the exposed inner surface of the disk, exposing the margin of the flange of said blank to radiant heat directed toward said margin while protecting the top of said blank from heat by the sealing gasket, continuing the application of radiant heat to the blank flange until the marginal portions of the flange are softened, the top of the blank remaining unsoftened, applying the blank to the mouth of the bottle to be sealed, pressing the top portion of the blank toward the bottle mouth suiciently to compress the gasket to seal the bottle mouth, and molding predetermined sectors of the softened marginal portion of the cap flange blank about the bottle bead leaving reinforcing ribs between the molded sectors.

ELVIN M. BRIGHT.

(References on following page) EEFEEECE'S @1111111 UNTTEE STATES 'PATENTS Numbr' 1 Number DSWrt Y FOREIGN PATENTS 1 Jmy 27', 1913 'country Dt A' Great Britain 11- 1 Aug; 18, 1922 

